1. Field of the Invention
This invention relates to a method of producing spherical-shaped polymer particles of ionic copolymers and copolymer or terpolymer base resin of the ionic copolymers and to spherical-shaped polymer particles having a rough surface.
2. Description of the Prior Art
It is known that thermoplastic polymers are useful in a finely divided or powder state for certain industrial applications such as coatings. In dry form the polymeric powders have been used to coat articles by dip coating in either a static or fluidized bed, by powder coating wherein the powder is applied by spraying or dusting, and by flame spraying. For this purpose, it is desirable to use polymer particles having optimum free flow properties. The prior art teaches that various polymers possess good free flow properties, if the particles consist of smooth spheres of fairly narrow size distribution. The smooth spherical particles may be produced by various methods, e.g., (1) formation of a dispersion of a thermoplastic polymer in a nonsolvent by mechanical or other means usually at a temperature above the softening point followed by cooling and recovery of the product, and (2) conversion of roughened and irregular particles to smooth generally spherical particles by a thermal or attritional means. In many instances the processes for production of the spherical particles involves the simultaneous comminution of the polymer and its dispersion in water at an elevated temperature and pressure followed by cooling and release of the pressure.